2004 P0108 Code MAP sensor failure

[Brian B.]

A few days ago the check engine light on my 2004 T-bird came on. I took the vehicle to Autozone and the reported error/problem code was P0108 which is described as concluding that the "Manifold Absolute Pressure/BARO Sensor had high voltage input for a predetermined period of time."

The "most likely" solution stated was to replace the manifold absolute pressure (MAP) sensor with a new mass air flow sensor part.

I was wondering if this might be one of the code problems that could possibly be resolved by either the commonly described simpler solutions of (a) adding some Sea Foam Motor Treatment to the vehicle and driving it to use the treatment to clean the fuel system or (b) cleaning or replacing the gas cap.

Alternatively, it would be also be helpful to know that these possible solutions are unlikely to resolve the issue and, instead, the best thing to do is to set up a service appointment to replace the manifold absolute pressure sensor that is cited as the most likely solution.

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[doug7740]

Fault code P0108 indicates that the MAP/BARO sensor operating voltage is greater than 5 volts. The MAP/BARO sensor is integrated into the EGR system module and is not serviceable separately. The EGR system module is located on the left rear side of the engine compartment.

Before you proceed with any further testing, disconnect the MAP/BARO sensor connector and turn the key on. Is fault code P0107 now displayed? P0107 indicates low voltage is detected at the MAP/BARO sensor. If P0107 is detected, replace the EGR system module.

If the MAP/BARO sensor is not defective, the MAP voltage at pin 3 (White/Green) of the EGR system module will have to be checked.



With the key ON, engine OFF, the voltage at pin 3 should be around 4-5 volts, depending on altitude. If the voltage is greater than 5 volts, there is either a short to power on the White/Green wire, or the Powertrain Control module is defective.

If the voltage at pin 3 is 4-5 volts, start the engine and the voltage should drop to 1-1.5 volts, depending on altitude. If the voltage does not drop with the engine running, check all vacuum lines and harness connectors for damage.

doug7740
1955 Thunderbird Blue